The straight key is the first thing that a person generally thinks of when they think of Morse Code. Such a key generally comprises a spring-loaded lever arm with a metal or plastic handle on the end. Pushing down on the arm closes a contact causing the transmitter to engage. Releasing it turns the transmitter off. Varying the length of time the transmitter is activated forms the basis of the dots and dashes.

Sending the code with a straight key requires practice before the operator is able to send well-timed dits and dahs. Doing this at speed requires more practice, after which you will develop a good "fist".

Morse operators back in the day developed wrist and muscle problems using the straight key to send fast code many hours a day. To make their job easier, the bug was invented.

The bug is an improved device for sending code. At its simplest, the bug comprises a longer lever arm mounted on a central pivot. On the operator end of the arm is a grip. The opposite end of the arm, where the contact is, is thinner and flexible so that it will bend. On this part of the arm is attached a counterweight; this weight is usually attached in such a way that it can be slid up and down the arm and then tightened to fix it in place. The operator moves the arm left to right instead of up and down. Moving the arm to one side closes the transmitter contact completely at the other end of the arm. Moving the arm to the other side causes the contact to open and the arm oscillate back and forth like a pendulum. This oscillation causes the contact to rapidly close and open, creating dits. The speed at which the arm oscillates is determined by the counterweight and where it is mounted on the arm. The bug greatly increased the efficiency of the operator's sending while greatly reducing the required hand motion.

Vibroplex is the company credited with creating the bug, and they still sell them. Original Vibroplex bugs are quite valuable and often sell for many thousands of dollars at auction.

The iambic paddle is a more modern creation, and is a mechanical/electronic hybrid. Such a key typically consists of a pair of finger paddles (sort of guitar pick like), oriented vertically side by side. The operator pushes on one paddle to make the dits and the other to make the dahs. Each paddle closes its own contact. The key is connected to the transmitter through an electronic "keyer" that sends dits or dahs as long as a paddle is held down. Most keyers have adjustments that allow you to adjust the send speed and the dit/dah "weight".

On such a key, the paddles are typically connected to the rest of the key through a series of springs/lever arms which provide paddle spring-back and tactile feel so the operator can tell when he has completely closed the contacts. Some more ambitious (read: expensive) iambic key designs use high-precision ball bearings and magnetic closures to produce the "perfect" feel.